Learn More
Cells are known to be surrounded by nanoscale topography in their natural extracellular environment. The cell behavior, including morphology, proliferation, and motility of bovine pulmonary artery smooth muscle cells (SMC) were studied on poly(methyl methacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) surfaces comprising nanopatterned gratings with 350(More)
A two-dimensional version of the transferred-echo double resonance (TEDOR) experiment is introduced to measure strong heteronuclear magnetic dipolar interactions between rare spins. A quantitative description of this 2D-TEDOR experiment is given for an I-S pair of spins undergoing relative motion. 2D-TEDOR calculations are consistent with data for a(More)
The fate of adult stem cells can be influenced by physical cues, including nanotopography. However, the response of human embryonic stem cells (hESCs) to dimensionally well-defined nanotopography is unknown. Using imprint lithography, we prepared well-defined nanotopography of hexagonal (HEX) and honeycomb (HNY) configurations with various spacings between(More)
A new class of epoxy nanocomposites with completely defined organic/inorganic phases was prepared by reacting octakis(glycidyldimethylsiloxy)octasilsesquioxane [(glydicylMe(2)SiOSiO(1.5))(8)] (OG) with diaminodiphenylmethane (DDM) at various compositional ratios. The effects of reaction curing conditions on nanostructural organization and mechanical(More)
Lifetime analysis of positronium annihilating in nanometer voids is used to study the thermal expansion behavior of thin, Si-supported polystyrene films near the glass transition temperature T g. A reduction in void volume expansion is correlated with a reduction in the apparent T g as film thickness decreases. Our results can be fitted using a three-layer(More)
An existing model that relates the annihilation lifetime of positronium trapped in subnanometer pores to the average size of the pores is extended to account for positronium in any size pore and at any temperature. This extension enables the use of positronium annihilation lifetime spectroscopy in characterizing nanoporous and mesoporous materials, in(More)
Bacteria that adhere to the surfaces of implanted medical devices can cause catastrophic infection. Since chemical modifications of materials' surfaces have poor long-term performance in preventing bacterial buildup, approaches using bactericidal physical surface topography have been investigated. The authors used Nanoimprint Lithography was used to(More)
The technique of positron annihilation lifetime spectroscopy ͑PALS͒ has been used to investigate the continuity and thermal stability of thin barrier layers designed to prevent Cu atom diffusion into porous silica, low-dielectric constant ͑k͒ films. Nanoglass™ K2.2-A10C ͑A10C͒, a porous organosilicate film, is determined to have interconnected pores with an(More)